Electromagnet.



A. A. ZIEGLER.

ELECTROMAGNET.

I APPLICATION rum J UNE6, 1912.

Patented Feb. 18, 1913.

2 SHEETS-SHEET 1.

ZUZZ/Y/e 5 5 6 3 A. A. ZIEGLBR.

ELECTROMAGNET.

APPLICATION FILED JUNE 6, 1912.

' 1,053,340. Patented Feb. 18, 1913.

2 SHEETS-SHEET 2.

Zk imes ses J7ZU6VZ%7'I' ALFRED A. ZIEGLER, OF BOSTON, MASSACHUSETTS.

ELECTROMAGNET.

Specification of Letters Patent.

Patented'Feb. 18,1913.

Application filed June 6, 1912. Serial No. 701,977.

To all whom it may concern:

Be it known that I, ALFRED A. ZIEGLER, a citizen of the United States,residing at Boston, in the county 'of Suffolk and State ofMassachusetts,have invented an improvement in Electromagnets, of whichthe following is a specification.

This .invention relates to electro-magnets; and has for its object toimprove the construction of the same to the end that the armature maybegiven acomplete quarter having a wide range of motion is required.

Figure 1 is a front elevation of an electro-magnet embodying thisinvention, the armature being in its retracted position. Fig. 2 is avertical section of Fig. 1, taken on the dotted line 22. Fig. 3 is ahorizontal section of Fig. 1 taken on the dotted line 33. Fig. 4 is aView similar to Fig. 3, the armature being attracted. Fig. 5 isa'perspective view of the armature. Figs. 6, 7 and 8 are details of theseveral plates composingthe armature. Fig. 9 is an enlarged sectionalView ofa portion of one of the plates, illustrating the scale on itssurface. Fig. 10 is a fragmentary detail of the polepiece and armature,the latter being in attracted position. Fig. 11 is a perspective view ofa modified form ofarmature, more especially designed for use with amagnet operated by a direct current. Fig. 12 is a horizontal section ofan electro-magnet,illustrating an armature embodying this inven tionwith a modified form of pole.

10, 10, represent a pair of magnet-coils arranged on cores connectedtogether by, a heel-piece 12, the forward ends of the cores beingextended or prolonged, as at 13, to form the poles. The poles; 13 areformed with opposing curved pole faces 14, and said pole faces areformed with transverse interdental spaces or grooves 15, each pole facehaving several such interdental spaces or grooves. An advantage offorming'the pole faces with interdental spaces or grooves is theproduction of a large magnetic surface; they also enable the employmentof an armature having portions of different leverage, as will bedescribed.

The armature shown in Figs. 1 to 8, inclusive, is especially designed tobe used with the electro-magnetwhen operated by an alternating current,and said armature is made S-shape, and is composed of a pile ofsuperimposed iron plates, partially insulated from each other andrigidly secured together. As here shown seven S-shaped plates areemployed, as 16, 17, 18, 19, 20, 21 and 22 and between the severalplates, or

most of them, separating plates 23 are pro-" vided. Some of the platesare made longer than others, as for instance, the plates 16, 18, 20 and22 aremade longer than the plates 17 19'and 21, and when said plates arerigidly secured together and to a center shaft 30, the longer plateswill project bethe outer'faces or ends of the armature will becomplementary with the opposing indented or grooved pole faces. The feetof the several plates, or most of them, are made of different length,but their heels are arranged in the same vertical plane, hence.

their toes terminate different distances from the back side of thearmature. This admits of the different plates entering the magneticfieldsuccessively and of the magnetic force actingincreasingly to pull thearmature in order that a full quarter turn may be given to it, and alsoto hold the armature in its full attracted position.

Referring particularly to Fig. 5, the feet of the short plates 17 and 21are made longest, their toes first entering the magnetic-field; the footof the plate 19 is made shorter than the feet of the plates 17 and 21,and next enters the magnetic-field; the foot of the plate 20is madeshorter than the foot of the plate 19 and next enters the magneticfield;the foot of the plate 18 is made shorter than the foot of the plate 20,and next enters the magnetic field and the feet of the plates 16 and 22are made the shortest of all and next enter the'magnetic-field. Theseparating plates 23 are made as long as the longest plates of the set,but have heels only, which lastly enter the magnetic-field. The aboveyond the ends of the shorter plates, so that may be otherwise arrangedthan as here shown, but when the opposing pole faces are formed withinterdental spaces the alternate arrangement of the short and longplates is necessary to form complementary outer faces. As a means topartially insulate the several plates from each other I prefer to takethe plates as they may come from the annealing furnace, without removingthe scale which is formed thereon, as shown in Fig. 9. The scale whichis formed on them affords a partial magnetic insulation which I findtoybe quite suflicient, although other means to partially insulate themmay 'be employed. In case the magnet is connected with a direct currentthe modified form of armature shown in Fig. 11 is preferably employed,although the armature above described will sufiice.

Referring to Fig. 11, the armature is composed of superimposed partiallyinsulated plates, some of which are made longer thanothers, but the feetof all the short plates are made the same length and the feet of all thelong plates are also made of the same length.

In bot-l1 forms of armature here shown, the outer faces thereof work onthe inside of the magnetic-field, where the magnetic pull is thestrongest. I

I find, in practice, that by making the plates composing the armature ofdifferent length and forming the opposing pole faces with interdentalspaces that a powerful pull is obtained, which is quite uniform duringeach unit of movement, and the semaphore. arm or disk attached to thecenter-shaft 30 or other work which it is desired to perform, will beuniformly and progressivelyaccomplished.

In the modification shown in Fig. '12, the opposing curved pole facesare not formed with interdental spaces and consequently the platescomposing the armature are all made of the same length, although theirfeet are of dilferent length, and I find in practice that such form isvery efficient, but notas efficient as the forms above described, eitherfor alternating or direct current work.

1. The combination with an electro-magnet having opposing pole facescurved and formed with transverse grooves, of a rotatable armature ofS-shape having its outer ends made complementary to said grooved polefaces, substantially as described. I

2. The combination with an electro-magnet having opposing curved polefaces with transverse interdental recesses, of a rotatable armature ofS-shape composed of'a pile of superimposed plates, some of which arelonger than others to thus form its outer faces complementary to saidpole faces, substantially as described.

3. The combination with an electro-magnet having opposing curved polefaces with transverse interdental recesses, of a rotatable armature ofS-shape composed of a pile of superimposed plates partially insulatedfrom each other, some of which are longer than others to thus form itsouter faces complementary to said pole faces, substantially asdescribed.

4. The combination with an electro-magnet having opposing curved polefaces with transverse interdental recesses, of a rotatable armature ofS-shape composed of a pile of superimposed plates, some of which arelonger than others to thus form its outer faces complementary tosaidpole faces, and some having feet longer than others arranged with theirheels in the same vertical plane, whereby their toes enter the magneticfield successively, substantially as described.

5. The combination with an 'electro-magnet having opposing curved polefaces, of a rotatable armature of S-shape having both of its outer endsformed with feet of different length, all of said feet being arrangedfor movement between said curved pole faces, thereby to work on theinside of the magnetic field, substantially as described.

6. The combination with an electro-magnet having opposing curved polefaces com posed of several plates made S-shape, and several separatingplates, all of said plates being arranged in a pile with the separatingplates between the S-shaped plates and rigidly secured together and to acentershaft, substantially as described.

7. The combination of an electro-magnet having opposing curved polefaces, of a rotatable armature composed of several plates made S-shapeand having feet of different length and several separating plates, saidplates being arranged in a pile with the separating plates between theS-shapcd plates and rigidly secured together and to a centershaft,substantially as described.

8. The combination with an electro-magnet having opposing curved polefaces, of a rotatable armature composed of several plates made S-shapeand several separating plates, said plates being arranged in a pile withthe separating plates between the shaped plates and rigidly securedtogether and to a Center-shaft and insulation between the severalplates, whereby theyare partially magnetically insulated, substantiallyas described.

9. The combination with an electro-magnet having opposing curved polefaces with transverse interdental recesses, of a rota table armaturecomposed of several plates In testimony whereof, I have signed my madeS-shape, some made longer than others name tothis specification, in thepresence of and several separating plates, all'of said two subscribingwitnesses.

' 4 plates being arranged in a pile with thelong ALFRED A. ZIEGLER.

5 and short plates alternately disposed to Witnesses form outer facescomplementary with the 1 B. J. NOYES, pole faces, substantially asdescribed. H. B. DAVIS.

